Ring rolling mill



Sept. 16, 1952 M. R. HEPPENSTALL 2,610,532

RING ROLLING MILL Filed Sept. 27. 1947 7 Sheets-Sheet l f INVENT OR.

I QW- M. R. HEPPENSTALL Sept. 16, 1952 RING ROLLING MILL 7 Sheets-:Sheet 2 Filed Sept. 2'7. 1947 Sept. 16, 1952 M. R. HEPPENSTALL 2,610,532

RING ROLLING MILL.

FilecfSept. 27; 1947 7 sheets-sheet s I h INVEIWOR. BY

Sept. 16, 1952 M. R. HEPPENSTALL RING ROLLING MILL 7 Sheets-Sheet 4 Filed Sept. 27. 1947 IN VEN TOR.

Sept. 16, 1952 M. R. HEPPENSTALL RING ROLLING MILL 7 Sheets-Sheet 5 Filed Sept. 2'7. 194'? JNVENTOR.

p 1952 M. R. HEPPENSTALL 2,610,532

RING ROLLING MILL Filed Sept. 27. 1947 7 Sheets-Sheet 6 INVENTOR. M A

l 1952 M. R. HEPPENSTALL 2,610,532

' RING ROLLING MILL Filed Sept; 27. 1947 v sneets-sheet 7 INVENTORI (7 4x 2. l/EPPENJTALLi i atenteci Sept. 16, 1952 UNITED. sT ATE 4 fnngze'aouny MILL -MaxR. Pittshhrgh, 1 a assig'xior to Heppen'stalL-Company, Pittsburgh, Pa., a. corl This inventionrelates to ring ro'l H inziarticulaijrto mills fori'forming a shing articles such as'roller. bearing racesiand the like. It'is among the objects of the inverrtion to provide a millwhich; as co'mpared-tothe other mills of its'type; is relatively small {and ccmpact'so as to' occupy minimum. floor space,jwhich produces an improved product at an unusually high *procluctionirate, ,which reduces the numbepiof "workmen required to operate it; andg which, has various features that facilitate'j lqadihg, control t e oll n pr ssu a d. p rmit a :qu ck h ee 'b 'm ;js tines r'v rio l, ne; Si-i. i.. '1 rT -mi lipro idev mpri s .1 immeiin wh ch are rotatablymounteda pair'of horizontal shafts which'haveiyerticallydisposed faces" at their inner ends" that are formed I togen a the sides 01:" w i bla duri he o i g an ifini hi is operations." A" common? source of power for rota ting the; shafts isprovid'ed which preferably 'is a singlemotor having separatebeltdrivecom- 'nections to each shaft, and -one ,ojf the shafftsis mounted fQIITBOiDIQCaI movement to "andfir om "blank en a in position, the belt drive forrthis ,lsha ft being'jcarriecl by the-'shafts reciprocating hen mi pz a i c p c W hit a "D i he' te in tbeiblaa k tu pr ed 'enie i i p'fi edfb fme d e i qh' i r id E 1 7 64 a 'theiin er end of onetof thejshafts, the othershafjt h vi =m d =r ceiv eirece o med ti t I inner-grid, ll/IbstsuitablY, because of a particu- '1 arj apparatus 7 for:automatically,loading-blanks, the'shaftwhichi is' reciprocated'is provided with he e' 'en i e s a ionar sh ft be th 'mandrlv a ijffi 4 The diameter ,oi' he'b ji s increased'and-its ck ess j u i r n ai f fei ri enf o rlollf which is pressed" against the out'erperiphery of theblank by mechanism'whichacts" o the roll {support {In the preferreq formfth'e workroll is drii'fe rfrictiohally b'y .a 'pair of backing rolls,' and "'al'lfoi the rollsare 'ihouhted in a pivotal or rock ables bracket." The b ackin'g j rollshaves: belt idrive f om? t ppo t ZbYtMb K ;with? bracket also carries' fa' guide ignwhich is con:- staritly -urged against the outer periphery of the blank 1 and; functio sprihcipal'ly' to fmaint'ain the bla "continuously circular as its diameter increaseszf'i'lhe brac oekiiig iriechami'sm' most suitaljly is a pressure ive piston, the cylinder for {which is pivotallytj carried byf a vertically eg termed 'yoke: member of'lthe' mainframe, and

t 'i'i xi erh t e: b acket: jContwro 6- Claims. (01. 80-5) mechap'ismiisiricluded"ferlimitingfthefdow ward s,

ihaiifigJ-Verticali facfe smthat vm 'Ihepreferred embodiment of theflinvehtlon'is illustrated in the accompanying draw'ingsfof w ch i 1 1 V a Plan V w of th m Fi a side-elevation Fig '3--a "front *er'rdyi-ew showin the-"reciprocating mandrel+receivingport1 -the;rhill-movedflawayffrom the n ia drl 1 loadingiarid nioadirigfpqsition; similar to Fig;- 3 showingthe mill-i11 ring positior r Fig; 5? a-sectior1 alo g tlre' line Y F erl iggfi-a frragmentz 'y front p, t r fi edt i hQ- r.th tr is aftsand their housings; Figs. '7 anti 8] are tri e'tficviews showing,respectively, the slidingor eciproe'a-ting -p0rtion 0f the milland; that port-ion f the main framewyhich slidab-ly supports 'itf Fig: 9 a-vertical section'alo g lines of Fig.4; "and Mgr-10 a View take along-lines'QfFFitAi 1Referri g to-the drawings, anpl'i n particular to 24 e mill. frame, which" nre embl i s aihsil: low casting, incl desa base l-iwhich subportson marsnafi'sjisaam 14 whi h;

met 6, a e 'r tatabliz. mpuntedm not shafts 1,3 1 and 14 are jequ p blocks t13aandl l''a'; respectivel I ,Qvided'with headslil 9 land 1| prevent; a ring. [blank from spr rolled; ,Block dallis equi ped vwith? manarerzz,

and ljblock"; [3c .is provided lwithjfa rec receiving and. supp'ortingfthe Qofu r tiohgiri wall thicknessl arid the correS increase in, diameterjof, a ring blank? I between; thefacfeiof 'hiandr'el 22"ar1d'a that is" supporftecl inf explained;

' "i Housing' H; which rot'ata'bl'y' I is. af art 70 a d emTi' r ri io ab "('FigS'. 3' and 4)" thbfiis enemy-supported 611 face shaped, to receive wear plate 29.

6 of the frames central block section. Figs. '7 and 8 show this sliding fit, the corresponding sliding parts being apparent if Fig. 7 is visually inverted upon Fig. 8. Briefly, the sliding surfaces of face 6 (Fig. 8) consists of a wear plate 26, bolted to the top of the face, the portion of the frame below the wear plate being indented in the manner shown to form a-recess.28, below which isubol ted another wear plate 29 having ,a tapered bottom surface. Sliding head 25 (Fig. '7 is provided with an overhanging flange 31 provided with a groove or track 32 to which is bolted another wear plate 33 which slides upon wear plate 26 of the stationary frame section. {to assure a tight fit of wear plate 33in the track, wedges 34 may be driven along its sides. Below flange 3| of the sliding head, there is -bolted an elongate reciprocating member 36 which'rides in recessed portion 28 of face 6, and which is secured in a manner to be described to mechanism which reciprocates the sliding head, and below reciprocatin'g member 36 there is another groove3! I It will thus be seen'that the sliding head is solidly supported to slide smoothly and evenly.

f I The; mechanism for a reciprocating the sliding headr asmost clearlyseen in Fig. 3, consists of apressurecylinder 41 having a pistonconnected to a Distonrod 42 whose outer end is connected .toareciprocating member 36 so that the latter becomesapartofthe pistonrod and is so considered in the following description. The pur- .pose of, reciprooating" the sliding head by the pressure cylinder is primarily to permit loading and unloading of ri'ngs. 1- ','I he extent of the inward sliding movement .ofi-the head is adjustable to make provision for rolling blanks of varying widths. Referring to Figs. land 8, this adjustment mechanism is a setscrew 4'3,.which is threaded through a lug 44 formed on the outerend of piston rod 42, the screw .being providedat its inner end with a head. 46 which, when the sliding head is recipro'c'ated inwardly to the. desired extent, abuts a hardenedcircular stop disc 4.! secured to the stationary section of the frame. When the sliding head is reciprocated inwardly to the full extent permitted by screw 43,the upper portion are ringv blank 12 isengaged between the heads 11,9 and}: of rotatable shafts l3 and [4, after which work roll 24 may be lowered upon the periphery of the ring blank and the ring rolling operation commenced by the rotatingshafts.

It is a feature of the invention thatv shafts l3 and 14 are rotatedby separate connections from a single motor 48 mounted on platform 2 at the rear of the frame, the driving connections preferably consisting of two series of V-belts 49 and which pass around grooved hubs 52 and 53f {Fig.l) onthe armature shaft 55 of the motor 4. upper end to piston rod 42 which actuates the reciprocable head. Similarly, a second arm 64- is rigidly connected at its lower end to the rock shaft and is provided at its upper end with yoke arms 66 equipped with pins 67 whose inner ends lie in a groove formed at a side of hub 52. Thus, any longitudinal movement of piston rod 42 re- ,sults in-.a;like-.movement of hub 52 on armature :51, swinging arm 64 and yoke 66 which engages thehub, and in such connections the short links 58 and 59 that support the rock shaft permit ittoiloatto compensate for the straight line andaround grooved wheels 54 and56 attached to the outer ends of the shafts. To maintain jthej grooves of .hub 52 continuously in alignment with those of' wheel 54 inall positions of the reciprocable head 25, hub'52 is 'splined on armatureshaft 55 for rotation. thereby and for movements longitudinally thereof, and link mechan ism is provided to move the hub on its shaft as the jreciprocable head is moved. As shown in Figs. 2 and 3, such mechanism includes a rock shaft 51' whose ends are supported byshort links 58 and 59 that are pivotally connected to lugs 6| and- 62, respectively, of frame base I. An arm, 63 isrigidly connected-at its lower end to rockshaft Hand is pivotally connected at its movements-of the piston rod and hub.

q -Proper tightening of drive belts 49 and 51 is accomplished by providing slots 201 (Fig. 1) in motor platform-'2, bolting the platform to the base-through these slots, and providing a pair of setscrews 68 which bear against the rear ends of the frame.

, .For cooling the, rotating shafts duringthe rollingoperation shaft i3 is cooled by Water supplied through a pipe H and openings 12 (Fig. 6), the water pouring out of the mandrel-receiving recess of this shaft when the shaft is reciprocated outwardlyat the completion of a rolling operation. Shaft l4 has a similar water supply pipe 13 and openings 74 but, in addition, a'return line 16 is provided which discharges into a splash plate l7. through openings IS-and then escapes throughapipe l9.

During the rolling of the ring blank it isdesirable to use edging or. side rolls to finish thesides ofthe-ring and to prevent it from spreading. .V'Ihis isaccomplished by mounting the axis of one of shafts l3 and l4'atlan angle, to .the other-,.and. in. providing a conical Working face on one or both of the opposed vertical faces .of headsv I9 and 2l. .As seen in Fig. 6, shaft 13 is mounted ata slight upward tilt from the horizontal axis of shaft [4, and the blank engaging surface. of head [9 at 'the end of shaft l3' lies in a cone of such angularity. as to bring it into-a vertical plane when in engagement withthe blank. 'As-;shown, the entire working face of head 2! preferablylies ina verticalplane. It is apparent that, with. such an arrangement, during-therolling of theblank the only time that any portionofthe blank will beengaged on both sidesby the working faces'of heads [9 and 2| is when the blank is being rolled between mandrel 22 and roll 24. Thus, thepressure which the shaft head exertsagainst-the sides ,of the blanks is exerted simultaneously with the downwardpressure of the work roll.

Work roll 24,,throughwhichthe ring-forming pressure .isapplied, is mountedin a bracket 8| (Figs. 2 andf5) which, in turn, is pivotally or rockably attachedto central yoke 'Lof the mill frame-by means of a pivot rod 82 which extends through openings provided in thelower portion of-thebracket, the rod, beingreceived in a pair of -lugs 83 formed on-the Icentral yoke of the main frame. The bracket preferably is a single hollow casting and; includes a pair of upwardly extending bent arms 84, sidesISl and top cross bracesl88 and 89. The bracketv is rocked by meansv of 7 pressure --mechanism, which includes a piston rod ,9! to theoutercnd of which ;,the upper end of the bracket-ispivotally attached, the rod beingconnected toa iston in a pressure cylinder 92. .The cylinder pivotally supported bythe upper-ends of, yoke 1, and, for this purpose, a Pa s ate an i ar 'd se re ward the blank; Morei'specificallm-as the rocking;

motion ofi bracket '81 oomme'nces' the moven'lent of the roller along the face of the cam may :cause pressure to be exerted upon-cam roll l-iiIvor-pit may be foundi desirable toso shape the ca'r'n face that-the pressure 'normallyplacedfuponit will ba.

relaxed. i In either eyent, triangular bell-crank lever I29 pivots onthe axis of' its supporting =pin l'33=- and, in sodoing ffeith'er presses guide-archer arm I24 toward the blankor -allowsittoretreat frdm theblankw lithe camis so shaped that.v

the guiderollerretreats i from-the blanla the-retreating-- "action =isunder the influence of -tension spring-J28 and the cam roller isheldzagainst the Eromathe above it-may be gathered that during? the rockingmfthe bracket F8 location-ref guide roller [-22 with respect to -the blank is a function of the? contour of the face ofcam I32. 'Ihis-iace 1s -so contoured that, as the diameter or the-blank graduallyis increased; theguide roll exerts a--con-e stant pressure upon: the periphery -of the blank and holds the blank in' a truly circular position which isthe position in which the rotational axis oi the blank: is in alignment with the-axis ofthe mandrel and the work rollJ Of course,-.irrdeter-.; mining'the cam contour; co'nsiderationf is given to -the swing-ing of bracket =8! on"-- its fixed: pivot 82; the swinging (of bell crank lever "I 29'ion --its pivot I 33 carried .by the bracket;- and theswingingot the lower end-of'arm-124on its supporting; v I

link -l26. The contour-of the --face of theca'm therefore-is a matterwhichmustbe determined specially-for-the conditions-i each different ring rolling operation.

-It'is desirable to mount cam l-32 such'a mam ner-that-it-can-be adjusted verticallyaway from or-towarditscam roller, tension spring inseperating-at each such adjustment to again 'press the roller against the cam -face. Alsog- -the" cam: is mounted so that-it can'be adjusted to :and fro, along stationary cross piece 99 which supports'it. By such adjustments, a cam 'of a certainjcontour i'smade suitable for usein-rolling a large number of difierent sized blanks. Since adjustable mountings of the types described are well knownand can be carried out-in amy number of Ways, it is not believedthat a-showing of them is necessary.

The mill isprovided with mechanism for- -preliminarilypositioning blanks for rolling, which; 1 as-shown in Fig. 3 0rd, includes. a solenoid I36) having a vertically reciprocating armature 43"! that is piyotally connected to a floating rocker arm 138. This arm carries at its forward enda loading arm I39, the upper end of which is provided with a yoke shaped to receive and support a ring blank. As shown in Fig. -10, the yokeis formed of a pair of angles 140 adjustably secured by a bolt and' slot connection to the upper end of loading ram l 39} the adjustable mounting. -permittin'gthe yoke to be raisedorloweredto support different sizedblanks in the proper position for the reception "of mandrel 22. -The-solenoid and its connected-=parts are carried by and reciprocated withsliding-head 25, the solenoid being mounted in a bracket l4! extending downwardly from the head which supports rocker arm I38 and loading arm 13!). -"Ihe roc kerarm is connected at itsrearward end by a link {42 pivotallymountedpn a-pin-carried-m a--lug l-43Mwh-ich extends:

8 Y outwardlyacirom one: side or -bracket; I 4 I; and the loading-anmiis he'ld upwardly by az'swing'inglink l:44;'attached:to1the brackets 0th9r-Side.- -"AS will be appreciated, when the loading iarm; is'urais'ed into blank loading positi'on; swinging link 1 44 causes the arm and-its'=yoke-' to:move upwardly amIarc- 'and the woke is so=-mounted' on the :arm

that wlien it reaches 1 its uppermost position, its

' frictionally drive workingcroll 2 4 at substantially theperipheralrollings'peed of a ring blankiZlso that'suchroll will notslip 'on'the blankas itis rotated by mandrel 22 "and heads l9 'a'nd- '2 Hot shafts] 3 and 4.

At the beginning of a rollingoperationfsliding head2 5' is moved-awayfrom the stationary head to 't'heposition showninFig} 3 in which mandrel 22 is "'er1'tii'ely=-o'utside='0f recess 23 in-"shaftl3. With solenoid T36 energized'to'elevate its armature 1'3 l-g and'in consequence thereof to liol'd lo'ading arm 139 upwardly;- apreformed' ringblank is plaeed uponthe" yoke at the *up'per i end of such armwh ich sometime the blank that its central opening is in alignment w'itli mandi'el 2 2 "Sliding head then is moved 'to theposition shown in Fig. 4;-such movement being effected by-supplying pressure fluid to cylinder "4| whichm'ovespiston r0d36 inwardly, theo'uter end-of'which is attached-to sliding head 25. During such movemen-t of head? 5' thering blankisslid'uponmandrel' 'Z 2; and solenoid I -3 6 is deenergiz'ed; by means ofany suitable liiniting'switch actuated by'contact with themandrel; to permit loading 'arm1-39 to mo've' downwardly tothe'pos'itiorf shown in Fig. 4 Each ring blankfl 2 preferably presha'ped to'the'required size by'forging'it from asetion of a "round; suchsection containingthe required amountbf metal','usually steel, for-forming aring ofthe desired dimensions. i"The'centra1. vopening permitthe blank to be pushed u on mandrel '22 by new l9 of shaft 1 3, as just explained.

-"In al1 ofthereciprocating movements of head 2 5'; hubfiZfOfdriVing-beIt' 49 sue longitudinally upon armature's'haft 55 (Fig. 1) in direct proportiontd the movements-'ofthe head." This is done by rotating rockshaft-ST- (Fig; 2)" which connectedto' piston rod '36 by *ar1n 63' and is "connectedto hub 52 by arm 64." Th'e extent of movement of'slid-ing' head- 25 to thepo'sition 'shown" in Fig; 4 is deterniined'by the adjustment of'screw 43 2 (Fig-1-7l to such position'that its head '46 *engages stop disc 41 (Fig. 8) whenheadlS of" shaft tit): is in the reqnired po'si-tion for a rolling opera- Simultaneously with themovementbf head- '25 to -thezrolling position shown Fig; 4', theouter end 'ofswingingwbracket i8 1 is lowered :to' bring working iroll 24 a to its rolling position shown Figs. 4' and 6, (swine-lowering beingcontrolled by i Asa ring blank is being rolled, between mandrel 22-and roll 24,it is edged and prevented from spreading by the vertical working faces of heads 19 and 2! borne by shafts l3 and 14, respectively, and the blank is continuously maintained in cir- --.=1l o by guide roll; 122 borne by thel wer end of arm 24. The position of this arm for thus holding guide roll, l22.in its required .positionis controlled by cam I32 (Fig; 5) thro'ugh roller l3l, bell crank I29 and pivoted link I26, roller I3! bein'g maintained in contact with the cam bytens'ion-spring I28.

Alt the completion of a rolling operation, head 25 is moved to the position shown in Fig} 3 to permit the rolled ring to be removed from the mandrel, this beingdone by pressure fluid applied tocylinder Al, and the working roll 24 is elevated by causing bracketel to; swing upwardly, this being done by supplying pressure fluid to cylinder ,2. I n such position of the mill units the mill is in the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

I l. A ring-rolling mill comprising a pair of rotatably mounted horizontal and substantially axially aligned shafts having vertically disposed faces formed to engage the sides of a ring blank, a motor for rotating said shafts, a separate belt connecting each of said shafts with said motor, mechanism for reciprocating one of said shafts horizontally and axially to and from blank engaging position thereby shifting one end of its belt, linking mechanism actuated by said reciprocating mechanism to reciprocate the other end of the belt for said reciprocated shaft, a mandrel rigidly borne by one shaft, the other having a mandrel receiving recess formed in it, a horizontal work roll, and mechanism for pressing said roll against the periphery of said blank to roll the blank between it and said mandrel.

2. A ring-rolling mill comprising a frame, a pair of rotatably mounted horizontal and substantially axially aligned shafts having vertically disposed faces rigidly carried at the adjacent ends of said pair and formed to engage the sides of a ring blank, driving means connected to both of said shafts for synchronously rotating both the shafts, mechanism for reciprocating one of said shafts horizontally to and from blank engaging position, a mandrel rigidly borne by one shaft, the other having a mandrel receiving recess formed in it, a bracket mounted onsaid frame, a hori-' zontal work roll, wide-faced backing rolls for frictionally driving said Work roll, driving means for said backing rolls, mechanism for pressing said work roll againstthe periphery of said blank to roll the blank between it and said mandrel and a two-part suspension member providing the sole support for said work roll, said suspension member, backing rolls and backing roll driving means 1.10 being mounted on said bracket, one part of said suspension member rotatably supporting said work roll and resiliently pressingsaid roll against the backing rolls and the other part having an end/detachably secured to said bracket and the other end securing the support of the-work roll, whereby said other detachable part can be removed and .a work roll of a different size readily substituted. 1

- ring-rolling mill comprising a pair of rotatably mounted horizontal and substantially axially aligned shafts having vertically disposed faces rigidly carried. at the-adjacent ends of:v said pair and formed to engage and edge the sides :of aring blank, driving'mearisconnectedto both of "said shaftsfor rotating the shafts, mechanism for reciprocating one of said 'shaftshorizontally to candsfrom "blank. engaging position, a mandrel rigidly borne by one' shaft, the other shaft having'a' mandrel. receiving recess formed in.it,.a horizontal rotatablyemounted V and" frictionallydrivenworkroll, and mechanism foripressing. said roll against the peripheryiof said blank to roll the blank betweenit and 'said'mandrel, theaxis of one of said shafts being tilted upwardly from. the horizontal'axis of the other shaft andhaving a conical edgingface, said shaft being tilted to :po- 'sition thetapered portion of said conical facein a verticalplaneas-said tapered portion is passing between said mandrel, and said work roll, whereby the blank is engaged by both of said faces only as it passes between said mandrel and said work roll.

4. A ring-rolling mill comprising a frame provided with a pair of rotatably mounted horizontal and substantially axially aligned shafts having vertically disposed end faces formed to engage and edge the sides of a ring blank, driving means for rotating said shafts, mechanism for reciprocating one of said shafts horizontally to and from blank engaging position, a mandrel rigidly borne by one shaft, the other shaft having a mandrelreceiving recess formed in it, a bracket pivotally mounted on said frame to swing in a substantially vertical direction, a horizontal work roll borne by the outer portion of said bracket and adapted to cooperate with said mandrel to reduce the wall thickness of the ring, an arm pivotally supported by said bracket and provided at one end with a guide rollfor engaging the periphery of the blank while it isbeing rolled between said work roll and mandrel and at its other end with a cam roller,

a cam borne by said frame and means urging said with it, a second shaft rotatably mounted in saidv frame substantially in axial alignment with said first shaft, both shafts having heads provided With'vertically disposed faces formed to engage the sides of a ring blank, a motor for rotating said shafts, separate drive connections from said motor to each of said shafts, mechanism for reciprocating said sliding block and moving its shaft horizontally and axially to and from blank engaging position and thereby shifting one end zeta-s32 I1 01 itswdriving oonnection, :me'ans'r actuatedibyxsaid reciprocating; mechanism for" reciprocating-the oth'er endtofithe driving connections iorxthe shaft bnrnexby said sliding block,v a mandrelrigidly .ibornei-byoneshaft, theiother'shaftihaving asmanvertically disposed -:end.\faces formed :to engage and. efiga-theisidescof a :ring :blank, driving means Pier-rotating:said-shafts, mechanism forreciprdcating ronevlof said shafts horizontally tosand from fiilaarkxengaging position, a.mandrel rigidly borne hynne shaft; ithe: other :shaft having a mandrelrneceivingsirecessformed in it, a bracket pivotally mounted Onsaid'frametQrsWing ina substantially Werticaladirection, a horizontal'wor-k roll borne by t'hemuter portion of said :bracket and adapted to cooperate.with said mandrel to reduce the wall thickness of :the zring, an 1 arm pivotally "supported hy said bracket andiprovided :at .one .end with a guide roll tfor engaging periphery ofthe-blank' during rolling za cam for zcontrolling the pivotal movements "of :saidaarm,.and;resilient':means nr'g- "in'g said guide'roll away from said engagement and into engagement with said cam, said qoam beingfbrme'd to cause said-guideroll :to maintain a constantand sufficiient pressure .on the blank to ih'old-athe: blank: with its "rotational axis constantly parallel to 'the rotational axis of the'workarollr BEEERENGES GI'IED I The" following references are of reoord inith'e file of this-patent: v

'UNITEDSTA ICESQPA'I'ENTS a Number f Name 1 .Date

1,295 614: ,Scrimgeour' i --.Feb;-. 25,, 19.19 1,371,009 Von Philp Mar. '8, .1921 1,352,049 Taylor 1 .Mar. 22,1921 1,661,024 Venable 1 11 'Feb; 28,:1928. 1 688335 :Iversen Oct. 23, 1928 31;832581 Taylornnn- .NovLZi, :19-31 1,9195686- Damerell; July-.25,-.l93-3 FOREIGN PATENTS Number Country Date 4,837 Switzerland Apr. 2, .1892 

